Extended short-wavelength infrared spectrometer based on a single n-graded-p junction

Ultra-compact spectrometers have attracted significant attention for their potential applications in portable systems for biomedical analysis, environmental monitoring, spectral analysis, and astronomical observation. In this work, we propose a miniaturized InGaAs-based extended short-wave infrared (eSWIR) spectrometer based on a single n-graded-p junction with voltage-tunable optical response characteristics in the range from 1600 to 2100 nm. We combine this unique optical characteristic with a regression algorithm to realize the reconstruction of an unknown spectrum. The spectrometer achieves a high responsivity of 0.73 A/W at 1650 nm, and a low dark current density of 3.91×10 −5 A/ cm 2 at 200 K, corresponding to a calculated detectivity of 1.69×10 11 cm · Hz 1/2 /W. Such spectrometers compatible with standard III–V processes can offer a pathway to greatly promote the development of miniaturized spectrometers.